Petroleum lubricating jelly containing an aluminum soap, tricresylphosphate and tributylphosphite



United States Patent asssssz PETR'GLEUP/i LUBRECATENG JELLY COlJTAINING AN SGAIE, TRICREEYLPHQSPHATE ANB TREEUTYLPHQSIHETE No Drawing. Application Uctoher 18, 3.955 Serial No. 541,391

6 Claims. (Ci. 252-372) This invention relates to improved petroleum lubricating jellies and, in particular, to thixotropic petroleum lubricating jellies having high dropping points, 10W coefficients of friction, and low oil separation characteristics.

in certain types of lubrication there are encountered conditions under which neither greases nor liquid oils are entirely satisfactory lubricants. For example, in the lubrication of ball bearings and other open bearing surfaces, particularly in relatively fine and intricate mechanisms such as cash reg rs and measuring instruments including airplane instruments, it is desirable that the lubricant be of such consistency that it will remain between the working surfaces and not be lost by dripping or leakage. At the same time, it is desirable that the lubricant be of relatively low viscosity under operating conditions, so as not to impede the operation of the mechanism. Liquid oil is not suitable because it will leak, while most greases are too viscous.

For this type of lubrication, petroleum jellies having thixotropic properties, that is, of jelly-like consistency when quiescent and liquid when agitated, have been recommended. These thixotropic petroleum jellies are mixtures of lubricating oils with waxes having melting points above about 120 F; and generally have a soap incorporated herein. These compositions have proved to be satisfactory lubricants under most conditions; however, they are subject to the disadvantage that they have relatively low dropping points, have poor wear properties and are rather unstable with respect to oil separation characteristics.

it is, therefore, an object achieved by this invention to provide thixotropic petroleum jellies having high dropping points, low wear properties and low oil separation characteristics.

This and other objects achieved by this invention will become apparent in the following detailed description thereof.

We have discovered that when a mixture of tricresylphosphate and tributylphosphite is incorporated in thixotropic mixtures of wax, aluminum soap and oil having a viscosity of at least about 145 SUS at 100 F., compositions resuit which while retaining their thixotropic properties have considerably higher dropping points, improved wear properties lower coefficients of friction and lower oil separatzl c-eristics than sir iar compositions prepared from 0118 having lower viscosities and containing iEciLilii tricresylphosphate nor tributylphosphite. he combination of properties obtained by the Ear composition or" he invention makes such a comarly valuable in certain types of lubricawitn lm'gn dropping pointand low oil separation, these compositions are better retained in the bearings at elevated temperatures; and because of their relative softice ness at low temperatures, as indicated by their high penetration and low running torque at low temperatures, they function satisfactorily as lubricants over the broad temperature range to which such bearings are subjected.

In preparing the improved thixotropic jellies of our invention, wax of high meltingpoint, advantageously wax substantially free from oil and having an ASTM wax melting point above about 120 F. is used. Ceresin wax such as is obtained from ozokerite having an ASTM wax melting point of about 160 F. has proved particularly satisfactory although other waxes may be used, such as beeswax, paraffin wax, petroleum ceresin, or refined rod wax, montan wax, shellac Wax, or mixtures of these waxes With oil-free petroleum waxes having melting points above about 120 F. The amount of wax may be varied widely, depending upon the particular wax used and the properties desired in the lubricant. In general, the amount of wax used should be sufficient to provide an oil-wax mixture having a cloud point above about F. In orderto obtain this cloud point, at'least about 4.0 percent by weight of wax having a melting point above about F. is usually required. Generally, it is not necessary to employ more than about 28 percent by weight of wax.

The oil used in forming these thixotropic jellies is one having a viscosity of at least about SUS at 100 F. While lubricating compositions result when an oil having a viscosity below about 145 SUS at 100 F. is used, such compositions are less desirable because they are less stable, i. e., oil separates when the composition remains quiescent and considerable loss occurs at elevated temperatures as a result of evaporation. We have found that a composition prepared from an oil having a viscosity of at least about 145 SUS at 100 F. has improved oil separation and evaporation characteristics. While the minimum viscosity of the oil which we can use is about 145 SUS at 100 F., the maximum viscosity can be as high as 4000 SUS at 100 F. Under certain appropriate circum stances an oil having a viscosity approaching this upper oleate, palmitate or other compound of aluminum with a high molecular weight fatty acid. Mixtures of aluminum soaps can also be used and we have obtained very good results withmixtures for example of aluminum di-stearate and aluminum tri-stearate. The aluminum soapis incorporated in thixotropic mixtures of wax and oil in such amount that the ratio of soap to wax is substantially less than 1:1, the soap is completely taken up by the wax and does not act as a thickening agent for the oil. We have obtained satisfactory results using ratios of soap to Wax as low as 1:15. In most cases We have found it advantageous to use ratios of soap to wax between 1:15 and 1:5 by weight. The jellies become less thixotropic with higher ratios of soap to wax while their melting points increase and their mechanical stability is improved. The composition resulting after the aluminum soap has been added retains its thixotropic properties and has ahigher penetration. and a lower running torque at low temperatures than the original-wax-oil mixture.

The tricresylphosphate and tributylphosphite are ad- 7 vantageously incorporated in the composition in amounts V v 3 ;V r such that the weight ratio butylphosphite is between about 1:1 and about 8:1. The total amount of tricresylphosphate and tributylphosphite added to the composition can be varied the optimum agents normally added to greases for a specific purpose 'such as anti-oxidants, corrosion inhibitors, and the like, Withoutadversely afifecting the beneficial properties derived bythe'composition of this invention.

For example, in instances where the petroleum lubricating jelly is subjected. to prolonged use under. oxidizing-conditions, we advantageously incorporate in the lubricating jelly a small amount of an oxidation inhibitor such as an alkali insoluble phenol, i. e., 2,6-di-tertiary butyl-4-methylphen01; 2,4,5 tri tertiary-butylphenol, etc.,- and/or a small amount of a diaryl amine. As examples of some of the diaryl amines which may be used in the compositions of our invention may be mentioned diphenylamine, phenyl alpha naphthylamine, phenyl-beta naphthylamine, alpha alpha-,

of tricresylphpsphate to tri- 4 V V l as under extreme temperature and pressure, the diaryl amine requirement-will be much greater than when relatively mild operating conditions are encountered. Generally, the amount of anti-oxidant employed is between about 0.1 and 1.5 percent by weight based upon the weight of the total composition. In any case, an amount sufficient to substantially inhibit oxidational deterioration is employed. 5

Other materials which can be added for special purposes include lubricating'powders such as powdered molybdenum sulfide, graphite, lampblack, mica or mixtures of one or more of these. materials. V

'In compounding these'thixotr'opic lubricants the aluminum soap and about 75 percent of the oil are'added' to a kettle equipped with a stirring device. The oil and soap are then stirred 'at room temperature until the soap is thoroughly dispersed in the oil. The mixture is then a heated,'with continued stirring, to about 250 F.

maintaining the mixture at about 250 F. the wax is added and stirring is continued until all the wax is melted.

alpha beta-,' and beta beta-, dinaphthylamines, and the like. Other diaryl amines aswell as their derivatives wherein one or more hydrogen atoms, on one or both of the aromatic nuclei are replaced by a substituent group may be used. The substituting group may, for example, be one selected from the class ofaryl, alykl, amino,

aryloxy and alkyloxy radicals, so long as the presence of the substituentdoes .not render the diaryl amine insoluble in oil, or soluble in water or oth erwise adversely afiect the efiectiveness ofthe diaryl amine... The amount of the diaryl amine employed will depend to a large extent upon the severity of the conditions to which the composition is subjected, as well as the particular diaryl amine used. For instance, when the composition is subjected to prolonged use under oxidizing conditions, such About'90 percent of the remaining oil is thenadded and stirring is continued until the mixture'is' homogeneous. Tricresylphosphate and tributylphosphite are added to the remainder of the oil which is then stirred into the heated mass.

If an oxidation inhibitor or other oil additive is employed itis. advantageously added to the portion of the oil to which the tricresylphosphate and tri butylphosphite are added. After further stirring the en.

tire formulation for about '10 minutes, the melted mixture. is poured into any desirable container and cooled under regulated conditions.

' In instances where a lubricating powdersuch as, for

example, lampblack or graphite is added the aboveprocedure is again followed with the exception that only about percent ofrthe total oilis admixed with the soapin the first instance. Then, after the wax has been melted into the mixture the lubricating powder, dispersed in about percent of the remaining oil'is added. The subsequent steps are as outlined hereinabove. V

Theadvantageous properties obtained by incorporating a mixture of tricresylphosphateand tributylphosphite in.

B G D E F Composition, parts by weight:

Oil A (58 SUS at F.) Oil B S US at 100 F.). Oil 0 (1165 SUS at IOQ F.) 78. White Ceresin Wax- .18. Aluminum Stearate. 4. Trlcresylphosohat 0.4. Tributylphosphiten 0.1 Diphenyl amine V 0.2 2,G-di-tertiary-butyl-4-methylphenol. Graphite Properties:

Penetration: ASTM D 217- Unworked at 77 F 198. I Worked at 77 F 380.

Consistency: Miniature Gone and Plunger- Unworked at 85 F 163. Unworked at 30 F 31. Unworked at 0 F. 27. Unworked at 30 F 22. .Dropping Point, F.; ASTM D 566 203.

Falex Wear Test- N0. oflggrlegh; 30 min. 50 lb.. 3 hr.

Five pound load for 3 hr., percent wt.

Evaporation Loss, 14 days 158-160 F.,

percent wt. loss.

BEG Machine- Starting Torque; Gm.-Cm Running Torque at end of 20 min,

GEL-C111.

Ooeificient 1' Dynamic Friction (Steel v.

' Steel) Herschel Machine.

Oorrgtsioln Tests, 60 hrs. at 212. F.-

Copper- Do. Brass o ;do Do. Br Heavy stain Slight stai11 Do. Appearance and Stability Cracked and Cracked and Smooth; Smooth;

' checkered; Very Little 011 checkered; Very Little oil Little oil grainy; Considseparation. separation. grainy; Considseparation. separaerable oil sepaeieble oil sepation.

ration.

While a thixotropic oil-wax-aluminum soap mixture wherein the oil has a viscosity of at least about 145 SUS at 100 F., as compared with a thixotropic oil-wax-aluminum soap mixture containing neither tricresylphosphate nor tributylphosphite wherein the oil in said latter thixotropic mixture has a viscosity below about 145 SUS at 100 F. are illustrated in the preceding table.

It is apparent from the data tabulated above that a small amount of tn'cresylphosphate and tributylphosphite have a very beneficial effect in reducing the wear shown by the Falex wear test. It will be noted by comparing Composition A with Compositions B and C that Compositions B and C have improved wear characteristics and appearance. Compositions B and C also show less oil separation. The addition of graphite in Composition C had very little effect in further reducing the wear characterisn'cs.

The improved result obtained with compositions prepared from oils having a viscosity of at least about 145 SUS at 100 F. is shown by comparing Composition D with Compositions E and F. It will be noted that Compositions E and F show (1) reduction in wear, (2) reduction in evaporation loss, (3) improved appearance, (4) less oil separation, (5) higher dropping points and (6) lower coefficients of friction.

While our invention has been described with reference to various specific examples and embodiments, it will be understood that the invention is not limited to such examples and embodiments and may be variously practiced within the scope of the claims hereinafter made.

We claim:

1. A thixotropic petroleum lubricating jelly comprising a major amount of a petroleum lubricating oil having a viscosity of at least about 145 SUS at 100 F., about 4 to about 28 percent by weight of a wax having a wax melting point above about 120 F.; an aluminum soap in an amount such that the ratio of the soap to wax by weight is between about 1:1 and about 1:15; and about 0.1 to about 1.0 percent by weight of a mixture of tricresylphosphate and tributylphosphite, wherein the ratio of tricresylphosphate to tributylphosphite by weight is between about 1:1 and about 8:1.

2. A thixotropic petroleum lubricating jelly comprising a major amount of a petroleum lubricating oil having a viscosity of at least about 145 SUS at 100 F., about 4 to about 28 percent by weight of a wax having a wax melting point above about 120 F.; aluminum stearate in an amount such that the ratio of aluminum stearate to wax by weight is between about 1:1 and about 1:15; and about 0.1 to about 1.0 percent by weight of a mixture of tricresylphosphate and tributylphosphite, wherein the ratio of tricresylphosphate to tributylphosphite by weight is between about 1:1 and about 8:1; and an oxidation inhibitor.

3. A thixotropic petroleum lubricating jelly comprising about to about percent by weight of a petroleum lubricating oil having a viscosity of at least about 145 SUS at F.; about 4 to about 28 percent by weight of a wax having a melting point above about F.; aluminum stearate in an amount such that the ratio of aluminum stearate to wax by weight is between about 1:1 and about 1:15; and about 0.1 to about 1.0 percent by weight of a mixture of tricresylphosphate and tributylphosphite wherein the ratio of tricresylphosphate to tributylphosphite by Weight is between about 1:1 and about 8'1 4. A thixotropic petroleum lubricating jelly comprising about 70 to about 90 percent by Weight of a petroleum lubricating oil having a viscosity of at least about SUS at 100 F.; about 4 to about 28 percent by weight of a wax having a melting point above about 120 F.; aluminum stearate in an amount such that the ratio of aluminum stearate to wax by weight is between about 1:1 and about 1:15; about 0.1 to about 1.0 percent by weight of a mixture of tricresylphosphate and tributylphosphite wherein the ratio of tricresylphosphate to tributylphosphite by weight is between about 1:1 and about 8:1; and about 0.1 to about 1.5 percent by weight of a diaryl amine.

5. A thixotropic petroleum lubricating jelly consisting of about 78 parts by weight of a petroleum lubricating oil having a viscosity of at least about 145 SUS at 100 F., about 18 parts by weight of ceresin wax, about 4 parts by weight of aluminum stearate, about 0.4 part by weight of tricresylphosphate, about 0.1 part by weight of tributylphosphite and about 02 part by weight of diphenyl armne.

6. A thixotropic petroleum lubricating jelly consisting of about 78 parts by weight of a petroleum lubricating oil having a viscosity of at least about 145 SUS at 100 F., about 18 parts by weight of ceresin wax, about 4 parts by weight of aluminum stearate, about 0.4 part by weight of tricresylphosphate, about 0.1 part by weight of tributylphosphite, about 0.2 part by weight of diphenyl amine, and about 0.1 to about 1.0 part by weight of 2,6-di-te1tiary-butyl-4-methylphenol.

References Cited in the file of this patent UNITED STATES PATENTS 2,320,002 Lutz et al May 25, 1943 2,383,916 Morgan Aug. 28, 1945 2,652,362 Woods et al Sept. 15, 1953 

1. A THIXOTROPIC PETROLEUM LUBRICANTING JELLY COMPRISING A MAJOR AMOUNT OF A PETROLEUM LUBRICATING OIL HAVING A VISCOSITY OF AT LEAST ABOUT 145 SUS AT 100*F., ABOUT 4 TO ABOUT 28 PERCENT BY WEIGHT OF A WAX HAVING A WAX MELTING POINT ABOVE ABOUT 120*F.; AN ALUMINUM SOAP IN AN AMOUNT SUCH THAT THE RATIO OF THE SOAP TO WAX BY WEIGHT IS BETWEEN ABOUT 1:1 AND ABOUT 1:15; AND ABOUT 0.1 TO ABOUT 1.0 PERCENT BY WEIGHT OF A MIXTURE OF TRICRESYLPHOSPHATE AND TRIBUTYLPHOSPHITE, WHEREIN THE RATIO OF TRICRESYLPHOSPHATE TO TRIBUTYLPHOSPHITE BY WEIGHT IS BETWEEN ABOUT 1:1 AND ABOUT 8:1. 